WORKSHEET 1: PYTHON CITY

The worksheet depicts a realistic scenario in the IT industry: You are employed as a programmer in a company and are supposed to continue a project of your predecessor. You are given a complex, executable programme as a template. Your task is to understand the programme and make certain adjustments.

The programme draws a picture of a city. As the programme code contains random elements, the city will look different every time you run the programme.

if random() < 0.4: meineFarbe = [0, 0, 0]

WORKSHEET 2: MONDRIAN

The programme randomly divides the GPanel window vertically and horizontally into coloured rectangles. The colours are randomly selected from the colours list.

The graphics are reminiscent of the artwork of painter Piet Mondrian.

Program:  [► WebTigerPython]   [► WebTigerJython]

# Mondrian.py
from gpanel import *
from random import *

def between(a, b):
    return a + (0.2 + 0.3 * random()) * (b - a)

def randomColor():
    while True:
        result = choice(colors)
        return result
    
def rect(xMin, yMin, xMax, yMax):
    for aColor in ('black', randomColor()):
        setColor(aColor)        
        fillRectangle(xMin, yMin, xMax, yMax)           
        xMin += delta
        yMin += delta
        xMax -= delta
        yMax -= delta
    
def maybe(bias = None):
    return choice([False,True,bias,bias] if bias!=None else [False,True])   

def draw(xMin = 0, yMin = 0, xMax = 500, yMax = 500):
    if xMax - xMin > threshold and yMax - yMin > threshold:
        if maybe(xMax - xMin > yMax - yMin):
            xMid = between(xMin, xMax)
            if maybe():
                draw(xMin, yMin, xMid, yMax)
                rect(xMid, yMin, xMax, yMax)
            else:
                rect(xMin, yMin, xMid, yMax)
                draw(xMid, yMin, xMax, yMax)
        else:
            yMid = between(yMin, yMax)
            if maybe():
                draw(xMin, yMin, xMax, yMid)
                rect(xMin, yMid, xMax, yMax)
            else:
                rect(xMin, yMin, xMax, yMid)
                draw(xMin, yMid, xMax, yMax)
    else:
        rect(xMin, yMin, xMax, yMax)

makeGPanel(0, 500, 0, 500)
colors = ['gray', 'lime', 'red', 'white', 'blue', 'yellow']
delta = 6
threshold = 100
setColor ('black')
draw()

WORKSHEET 3: BRAIN GAME

Game description:
The playing field consists of a lamp that can glow in red, yellow, green and blue, and is white when switched off.

There are also four circular buttons in red, yellow, green and blue. The lamp always displays longer sequences of random colours: first with one colour, then with two colours, etc. After each sequence is displayed, the player must repeat the sequence by pressing the buttons. If they do this correctly, the length of the sequence is increased by 1; if they make a mistake, the game is over. The aim is to achieve the longest possible sequence.

The problem is solved in 6 steps:

Step 1: Displaying the playing field
Use the following programme framework:

Program:  [► WebTigerPython] [► WebTigerJython]

# BrainGame0.py
from gpanel import *

def showLamp(col):
    pass

def showButton(number):
    pass

def setup():
    for i in range(4):
        showButton(i)
    showLamp(-1)
  
makeGPanel(-200, 200, -200, 200)
setColor("black")
fillRectangle(400, 400)
addStatusBar(30)
setup()

Write the functions according to the following documentation::

Step 2: Use the mouse to switch on the lamp in 4 colours
When you press the colour buttons, the lamp with the same colour is switched on. When you release the button, the lamp returns to white. Use the callbacks: onMousePressed(x, y) and onMouseReleased(x, y), which you must register with makeGPanel(). To do this, use a variable buttonIndex in the range 0...3 for clicks on buttons and -1 and -2 for clicks on white and black areas.

def onMousePressed(x,y):    
    if getPixelColorStr(x, y) == "red":
        buttonIndex = 0
    elif ...

    elif getPixelColorStr(x, y) == "white":
        buttonIndex = -1
    else:
        buttonIndex = -2    
    if buttonIndex >= 0:
        showLamp(buttonIndex)

def onMouseReleased(x,y):
    showLamp(-1)                
  
makeGPanel(-200, 200, -200, 200, mousePressed = onMousePressed, 
                                 mouseReleased = onMouseReleased)
  

Stept 3: Random sequences with the colours red, yellow, green and blue
Import the integer random numbers with from random import randint. Insert the following lines in the main section, which creates a list seq with n random numbers in the range 0..3. The number of elements in the sequence is set to n = 3 for testing purposes.

seq = []
n = 3
for i in range(n):
    seq.append(randint(0, 3))
setStatusText("Showing sequence with length " + str(n))    
showSequence()
  

Write the function showSequence() that displays these sequences. The display duration is set to 1000 milliseconds here.

def showSequence():
    for k in seq:
        delay(1000)
        showLamp(k)
        delay(1000)
        showLamp(-1)
  

Step 4: Repeat and check the sequence
After the sequence of three colours is displayed, the user begins repeating the colour sequence by pressing the buttons. If they make a mistake, the game immediately stops with an IsOver message, if they do it correctly, a success message is displayed.

The correct sequence is tested each time the mouse is released, i.e. in the callback onMouseReleased(x, y). To do this, the variable clickCount must be used to count the mouse clicks already made and with

if seq[clickCount] == buttonIndex: 
      clickCounr += 1
  

check whether the correct click was made. If this is the case, increase clickCount; otherwise, set a flag isOk = False. To inform the main programme when the test is complete, use a flag isUserActive.

global clickCount, isUserActive, isOk
if seq[clickCount] == buttonIndex: 
    setStatusText("Sequence confirmed")
    clickCount += 1
else:
    isOk = False
    setStatusText("Sequence false")
if clickCount == len(seq):
    isUserActive = False
    isOk = True
  

Once the entire sequence has been successfully tested, set isOk = True. The variables clickCount, isOk and isUserActive must be defined as global and initialised in the main programme. In the main programme, insert a wait loop that runs until the user action is complete.

isUserActive = True
isOk = False
while isUserActive:
    delay(10)
if isOk:
    setStatusText("Sequence confirmed")
else:
    setStatusText("Sequence false")    
delay(2000)
  

setup()
n = 1
while True:
    clickCount = 0
    setStatusText("Showing sequence with length: " + str(n) + "...")
    delay(2000)
    seq = []
    for i in range(n):
        ....
    
    showSequence()
    setStatusTex("Click tu repeat sequence")
    isUserActice = True
    isOk = False
    if isOk:
        setStatusText("Sequence confirmed")
        delay(2000)
        n += 1
    else:    
        break
setStatusText("sequence failed")

 if not isMouseEnabled:
      return